A Time-Resolved Line-Focus Acoustic Microscopy Technique for Surface-Breaking Crack Depth Determination

Nondestructive Evaluation of Crack Depth in Concrete Using PCA-compressed Wave Transmission Function and Neural Networks

“…However, accurate crack depth estimation from wave transmission remains a challenge. The socalled cut-off frequency value of the surface transmission function (TRF) has been applied to estimate crack depth in concrete [6,10,11], although the experimental determination of the cut-off frequency is not straightforward and the estimated crack depth may contain error [6].…”

“…Among them, mechanical wave (both body and surface waves) transmission methods demonstrate superior sensitivity to the presence of cracking along the wave path in concrete [5][6][7][8][9][10][11]. However, accurate crack depth estimation from wave transmission remains a challenge.…”

Time-Resolved Line Focus Acoustic Microscopy Using Lamb Waves for Material Characterization of Thin Plates

“…(1 ) (2) Fourier transform of the transfer function H of the lens-fluid-plate system Output voltage in frequency domain. Input pulse in frequency domain.…”

“…Time-resolved line-focus acoustic microscopy has proven to be a useful technique to measure the elastic near surface properties of anisotropic, homogeneous materials, see [1] and [2]. The time resolution of the signal can be done with a lower frequency compared with the V(z) measurement methods in which frequencies of 200 MHz or higher are used.…”

Acoustic, Electron and Optical Microscopy Visualization of Surface and Sub-Surface Cracks

“…[5] A focused transducer with a center frequency of approximately 50 MHz was used in conjunction with a Panametrics Hyscan system. [14] The specimens were submerged in a tap water tank for examination. The focused transducer, attached to x, y, z stages, was excited by a Panametrics Pulser-Receiver (Model 5601NST) to generate ultrasonic waves.…”